josephazannieri wrote:Yo Iain:
Glad to hear that it's progressing. There are a couple of ways to slow it down. You could just have somebody chuck that motor pulley into a lathe and shave it a little. Just a hundredth of a hair or less at a time, until you get it to turn at the right speed with the speed control centered. You will need to measure the speed by counting the number of turns over time. This is much more accurate than trying to measure by the number of turns in a minute or using a strobe, because most strobes don't give percentage fast or slow. I have a PDF one that I will send if you want, but it only shows 2 or 4 percent fast or slow. You could count the number of turns in 3 minutes because 33 1/3 times 3 is a nice even 100 revolutions. You could measure the length of time it takes you to do 200 or 300 revs with a digital stopwatch and see what that gives you for speed.
I think it is about 35 instead of 33 1/3. This was consistent. I'll let it warm up good and measure again. Please send the PDF.
josephazannieri wrote:Once you know percentage fast or slow, you can measure the circumference of the motor pulley (C = pi times d) and use the percentage to determine exactly how much to shave off diameter. You will need a micrometer or digital calipers. It's change of C that determines the change of speed. I would be real careful and have a machinist do it. You don't want to cut too much. There is probably a job machine shop that could help if you put the problem to the craftsman (or woman) there.
Bloody hell man you know I'm low tech ROFLMAO. Calipers micrometer wth : ) I'll ask some of my smart friends to see if they have any of these tools. I don't mind buying an extra pulling just in case.
josephazannieri wrote:Then there is also the quick'n'dirty way, which is to throw the TT on a Variac and cut the voltage till it comes to speed. Make sure that the speed control is centered when you set voltage. Some guys say that when you start cutting voltage, you lose some of the rhythmic strength of the Garrard because you cut motor power, and the thing that makes that 301 drive so hard is the fact that the motor is so strong. Using the brake reduces the voltage change required to get to speed.
This makes sense. I have a variac but I'd rather not fix it that way.
josephazannieri wrote:For what it's worth, I have had high compliance carts in relatively massive arms, with good results. I am not quite as concerned with the theoretical ideal as some are, because of the flexibility of cartridge compliance measurements, and the GIGO aspect of the theoretical formulas. Currently running an ADC QLM 36/III (1.2 G) on a stock Lenco L75 and it works fine. Traded it for a B&O SP-14 (2-3G), thinking it would help, and the B&O really stunk and I went back. That's for what it's worth. For me, if it sounds good, it is a success, regardless of theory. But there might be a benefit in going to a good MC.
I'll try the theoretical ideal for the experience. I'd like to try an MC cart anyway. It will be interesting to compare.
josephazannieri wrote:That's another too-long post. Hope you survived it. Glad to hear of progress! Your continued attention to correspondence keeps the readers interested. Good luck from the crude, chatty old guy,
Thanks again for the help and information.